Infrastructure

A portal into the bricked up canal that runs through the heart of Washington D.C.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

The hidden offices underneath Memorial Bridge have been locked up since 1976.

This supermarket is suspended 25 feet above an interstate highway.

This Victorian marvel of engineering and artistic prowess is nicknamed the "Cathedral of Steam."

The whole world in one water tank.

A water pumping station disguised as a residential home to assuage concerned neighbors now tricks most passersby.

The wooden telephone box hidden away in London's Piccadilly was the original prototype of the iconic kiosk.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

A derelict bit of transportation infrastructure hidden in the woods.

This hollowed salt dome is the largest oil storage facility in the world, hoarding 250 million barrels of crude oil.

Abandoned since the 1950s, the streetcar lane beneath the heavily trafficked bridge lays empty and unused.

One of the only spherical 19th century gas containers left today.

100 years later, they're still down there.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.